Intralayer carbon substitution in the MgB2 superconductor

Abstract

We report that the ternary MgB2-xCx compounds adopt an isostructural AlB2-type hexagonal structure in a relatively small range of nominal carbon concentration, x<0.1. The lattice parameter α decreases almost linearly with increasing carbon content x, while the c parameter remains unchanged, indicating that carbon is exclusively substituted in the boron honeycomb layer without affecting the interlayer interactions. The superconducting transition temperature Tc decreases quasilinearly as a function of the carbon concentration, with a slope steeper than that for the isoelectronic Mg1-xAlxB2.

abstract = "We report that the ternary MgB2-xCx compounds adopt an isostructural AlB2-type hexagonal structure in a relatively small range of nominal carbon concentration, x<0.1. The lattice parameter α decreases almost linearly with increasing carbon content x, while the c parameter remains unchanged, indicating that carbon is exclusively substituted in the boron honeycomb layer without affecting the interlayer interactions. The superconducting transition temperature Tc decreases quasilinearly as a function of the carbon concentration, with a slope steeper than that for the isoelectronic Mg1-xAlxB2.",

N2 - We report that the ternary MgB2-xCx compounds adopt an isostructural AlB2-type hexagonal structure in a relatively small range of nominal carbon concentration, x<0.1. The lattice parameter α decreases almost linearly with increasing carbon content x, while the c parameter remains unchanged, indicating that carbon is exclusively substituted in the boron honeycomb layer without affecting the interlayer interactions. The superconducting transition temperature Tc decreases quasilinearly as a function of the carbon concentration, with a slope steeper than that for the isoelectronic Mg1-xAlxB2.

AB - We report that the ternary MgB2-xCx compounds adopt an isostructural AlB2-type hexagonal structure in a relatively small range of nominal carbon concentration, x<0.1. The lattice parameter α decreases almost linearly with increasing carbon content x, while the c parameter remains unchanged, indicating that carbon is exclusively substituted in the boron honeycomb layer without affecting the interlayer interactions. The superconducting transition temperature Tc decreases quasilinearly as a function of the carbon concentration, with a slope steeper than that for the isoelectronic Mg1-xAlxB2.